Synthesis and mesomorphic behavior of chiral partially fluorinated liquid crystal incorporating S-2-methylbutyl

Three different smectic liquid-crystalline 4,4'-biphenyl derivatives within the fluorinated series and incorporating S-2-methylbutyl moiety have been prepared and their mesomorphic properties investigated. The synthesis of th ese compounds have been carried our from 2-F-hexylethyl iodide or 2-F-hexyl ethanol. The spacer linking the fluorinated tail to the mesogenic core was a carboxylate, an ether or an oxycarbonylmethoxy function. The ether functi on lead to an increase of the melting and clearing temperatures with a redu cing of the span of the mesophase. The physical properties of these novel f luorinated materials are commented and illustrated by the study realized fr om the differential thermal analysis and the light microscopy.